System and apparatus employing the hall effect



Sept. 8, 1931. 1,822,129

SYSTEM AND APPARATUS EMPLOYING THE HALL EFFECT P. H. CRAIG Filed July 9, 1926 2 Sheets-Sheet l 754C Source B 'IIIIIUIIIIIII dwr l A 31:5.. E f

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ATFURNEY Sept. 8, 1931. P. H. CRAIG 1,822,129

SYSTE AND APPARATUS EMPLOYING THE HALL EFFECT Filed July 9, 1926 2 Sheets-Sheet 2 lr. E;

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BY ATTORNEY Patented Sept. 8, 1931 UNITED STATES PATENT OFFICE PALMER HUNT CRAIG, oF CINCINNATI, oHIo, AssIGNOR To TNvEx CORPORATION, A CORPORATION OF NEW YORK SYSTEM AND APPARATUS EMPLOYING THE HALL EFFECT Application filed July 9, 1926.

.y My invention relates broadly to electrical apparatus for modifying the character of electrical current and more particularly to an apparatus for effectively employing the transverse potential difference in certain metallic plates when subjected to the action of a longitudinal current and the influence of a magnetic field.

One of the objects of my invention is to 1U provide a device consisting of a plurality of rectangular metallic foil sheets or metallic alloy plates in stacked arrangement insulated one from another and electrically connected in parallel at opposite ends thereof and in i5 series along the transverse axis thereof,

whereby current of direct current characteristic may be secured in a circuit which connects to points along the transverse axes of the plates when alternating current is sup im plied to the opposite end of the plates and a magnetic field created around the plates.

Another object of my invention is to provide a construction of fixed rectifier for alternating current which remains in permanent 2b adjustment and does not require resetting from time to time.

Another object of my invention is to provide a device for modifying electrical current of alternating characteristic for rectifying, amplifying or causing the generation of electrical oscillations of any selected frequency.

Still another object of'my invention is to provide an electrical apparatus particularly adapted for operation in conjunction with the circuits of a radio receiving system for rendering feeble signal currents observable.

A still further object of my invention is to provide an apparatus unit which may be connected in circuit with electron tube apparatus for facilitating the operation of the electron tube apparatus in the reception of signaling energy.

Other and further objects of my invention 415 will be understood from the specification Serial No. 121,394.

hereinafter following by reference to the accompanying drawings in which:

Figure l represents in perspectiveview the arrangement of parts in the apparatus of my invention; Fig. 2 is an end view of the apparatus showing more clearly the direction of the magnetic field perpendicular to the plane of the metallic plates; Fig. 3 is a schematic view showing the arrangement of the metallic films which comprise the apparatus of my invention; Fig. 4 is a diagrammatic view showing the wiring arrangement of the apparatus of my invention when used as a rectifier; Fig. 5 shows one of the applications of my invention in a reflex signaling receiving circuit Fig'. 6 illustrates an application of my invention as a detector in a radio receiving circuit; Fig. 7 shows a circuit arrangement which makes use of the principles of my invention in the amplification of signal energy; provision being made for facilitating the production of oscillations; Fig. 8 shows a circuit arrangement wherein the longitudinal current which passes through the plates of the apparatus of my invention is derived from a source independent of the source which creates the magnetic field about the plates; Fig. 9, illustrates a circuit arrangement employing a plurality of the devices of my invention as an amplifier of incoming signaling energy and as a rectifier of the amplified energy; and Fig. l0 shows the fundamental arrangement of the magnetic field transverse to the plane of the several metallic -lms in the apparatus for developing the I=the current (longitudinal) through thel strip; d r--the thickness of the strip. H=the magnetiefield strength.V Y The Corbino effect is similar to the Hall effect, wherein a radial current through a circular disc subjected to a magnetic field perpendicular to the plane of the disc, produces a circular current throughthe disc.

I have discovered that if plates or films 'of metal such as bismuth, tellurium, bismuthantimony alloy,or other 4metal or alloy, be connected as shown in thedrawings, the device will act asa practical electrical rectifier of impressed alternating currents. Referring to the` drawings in Fig. 4, the. alternating current issent through the strip 1 from c to d, in one-half of thecycle, and from d it enters the solenoid S, being an air core or a core of magnetic. material, thence after passing through the solenoid it returns to the,

alternating current source. Inthe other half of the cycle-theoperation is, of course, reversed.

Fig. 4alsovshows the method of stacking many plates 1, 2 and-3 on top of one another, with suitable insulation between, and then connecting the positive Hall7 effect potential point of one plate tothe negative Hall effect potential point of the one below, as represented in' the drawings at e, f, g, h, i and j. In other words, the transverse potential ofall of the plates 1, 2 and 3 are put in series in order to add up to larger values of potential than would be obtained with a single plate.v

It is obvious, that sincethe polarity of the Hall -effect potential difference changes in synchronism with either the change in polarity of the points c and d, or with the change in direction of the magneticv flux through the plate, the polarity of thepoints e, j, (Fig. 4)

will always be the same -with respect to each.

other when both the magnetic fiux and also the longit-tdinal current through the plates change in phase synchronously with each other. The arrangement shown in Fig. 4 will then obviously give a pulsating direct current at the points e, j.

The construction of the apparatus of my invention is more clearly illustrated in Fig. 1 where the metallic films have been rep-- the metallic films. 1

resented at 1, 2, 3, 4 and 5 separated by insulated sheets 7. Opposite ends of the films are tapped as represented at c and d. The transverse axes of the films are connected in series as represented at e, f, g, h, z', j, k, Z, m, and n for delivering a direct current. The end view of the apparatus in F 2 shows more clearly the arrangement of the films and the dielectric sheets. The solenoid Winding has been divided into two sections for producing a transverse magnetic field through In Fig. 3 I have shown a stacked arrangement of metalhc films separated by insulated sheets in accordance with my invention, where the alternating current I passes along the longitudinal axes ofthe films from d to c. I provide copper end contacts 8 and 9 which bridge all of the metallic films enabling the films to be connected in the electrical circuit in parallel. The point contacts across the transverse axes of the films have been represented at a and a.

The device may be used as a rectifier in ordinary electrical circuits where the power drawn from the rectifier is of sufficiently low value-so as to render'the method practicable. The arrangement can also be used as a rectifier in radio transmitters and receivers, especially to replace the crystal detector or the triode vacuum tube detector in radio reception. It could be used either alone or in combination withelectron tubes, a typical circuit diagram of the latter method being given in Fig. 5.v l

Referring to Fig. 5 in more detail the receiving antenna system is represented at 10 which connects to a ground system at 11 with a coupling inductance 12 therein coupled'to the tuned input circuit 14 of the electron tube 15 which functions as a radio frequency amplifier. The outputof the radio frequency amplification circuit 15 connects through a tuned circuit 16 with the input circuit of a second stage of radio frequency amplification constituted by electron tube 18, the output circuit of which includes transformer system 17 tuned as represented at 2S for supplying exciting current to the solenoid S through a series circuitA which passes through the longitudinal axes of the metallic films from points d to c. A direct current is derived across the polnts of contact a and a which is directly proportional to the lncoming signaling energy. The rectified current is deliveredthrough a transformer system 20 to the input circuit of the electron tube 18 which also functions as an audio frequency amplification system deliveringits audio frequency output through transformer 1t) with the input circuit of electron tube 15 which serves also to amplify at audio frequency delivering its output to telephones '.l. Battery A supplies filament heating current. for the several tubes while battery B supplies space current for the tubes. Tlietuned system 17;.28

- permits a relatively large value of current tol pass through the metallic films andi thereby secure maximum 'direct current energy across 'the-transverse 'axes ofthe metallic films. My invention kmay be 'appliedto all standard circuits as Well as to` thereflex system of Fig.5. f i

- Referring to Fig. 6 a simplified circuit as illustrated shoWing'the application of the principle lof myinvention to a simple radio receiving apparatus?L In this circuit thein- 4coming sigii'alingfenergy delivered from' tuned circuit 14 passes through the longiin the reproduction of radio telephone signals :and voice, and is, therefore, far superior to either the crystal detector or the electron tube from the standpoint of faithful reproduction, in addition to its superior qualities of stability7 ease of operation and lower cost of maintenance. Y

' -F ig. 7 illustrates a circuit arrangen'ient 4which I employ inthe amplification of signaling energy by means-of the apparatus of-my invention. An inputvcircuit lhas been illustrated inthe form of an inductive coupler 1 25 timed Vby variable condenser' 26 and con` nected through the longitudinal-axes of themetallic films at (Zand c.' ik permanent mag netic field maybe established about the metallic films by means of a local source 2l connected in circuit-with the Winding' S. An

- iron core 'may be provided for'this solenoid S. 'Incoming signaling'energy is' supplied through winding 27 coupled'v'viththe Wind' ings 25.

The transverse axes of the fili-ns at a and a are connected in series with a local source 22, and an inductance Qtivhich couples with the inductance system'25. degiee 'ofA regenerative ainplificatioi'i is thus introduced for increasing the amplitude of the impulses of signaling energy delivered to the output circuit. lThe principle of my invention may beappli'e'd to an oscillator Where the input coil 27 connects to a small local eX- citer'of alternating current andthe output connected through ak transformer system. By employing selected values of inducta'nce, capacity and resistance the syste'mpniay'be arranged to oscillate at either audio or radio frequencies.

Fig. 8 illustrates a nieth'od'of obtaining greater energy 'amplification in the appara- A desired Winding S.

Vtus of my invention. A permanent magnetic flux is set up through the thickness ofthe plates 'and also a permanent longitudinal currentis established along the horizontal axes of the plates from. a battery 28. A tuned input circuit system 27-25-26 is arranged to excite the Winding s which encloses the stack of alternately positioned films and dielectric sheets. lThe longitudinal axes of the films are connected at points@ and a with an out-` put circuitincluding a source of potential'QQ, and -inductance 24. The inductance 24 is inductively coupled toan inductance 29 tuned by means of condenser 30 in the output circuit of the electrical system. The fluctuating magnetic field fromA the Winding S `which varies in proportion to tlie-amp1itude-of the signaling energy is superimposed on the permanent field which is established.

The input may also be superimposed on the longitudinal current instead of upon the magnetic field. The local battery for supplying longitudinal current to the conductive films may thus be eliminated. The local battery 22 'in the cii'cuit of the electrical system is provided to boost the voltage of the output tothe proper value for the operation of succeeding amplifier stages -or the reproducing unit, the Hall fluctuating potential being then superimposed upon this steadypoten`A tial. By increasing the number of conductive films in parallel the effective potentialmay alsobe increased.

`In Fig. i) I. have shown an application of -iny invention to an4 electron tube circuit' .Where the conductive films have their longitiidinal axes connected in series in the output circuit of electron tubefl. A constant magnetic field is supplied from battery Qlto' the Winding S. In this manner the device operates as a radio frequency amplifier, delivering amplified energy to an output cireuit'across the transverse axes of the conductive `films in series as representedat e and j, the output circuit including battery 22 and solenoid winding S. The solenoid winding S connects in series with the longitudinal axes of conductive films as represented at 'o' and d and across the transverse axes ata and a I connect the output circuit which includes the battervl 22. The arrangement of the conductive films Within the -solenoidal Winding S serves as a rectifier of amplified energy delivered by the conductive films Within-the solenoidal Fig. lO'shoWs a method I may employ for setting up the magnetic field which threads throu'glithe conductive films. A pair of compressed silicon steel filing cores or other suitable inagnetic material or alloys are arranged on opposite sides of the stack of alternately positioned' conductive films and dielectric sheet-s. On these coi'ls are providedv the Windings S2 and S3. supplied from the local source 21'. The stack of bismuth or metallic alloy -curing desired operation.

conductive films may he quite thick but the magnetic eld is concentrically normal to the plane of the conductive films. Permanent magnets may Valso be employed instead of electromagnets.

It will be understood that I rnly employ conductive films of alloys, metals, crystals or chemical salts in lieu of the bismuth films mentioned herein. Photo-electric materials may be provided for the films. In some instances, I may produce the bismuth films by eathodic sputtering, thus making the films very thin. The transverse current effect is inversely proportional to the thickness of the film and when the films, which are often so thin as to be transparent to light, are deposited on thin mica approximately 10() films are connected in series transversely for se- Ihe magnetic field in some cases is produced by a solenoidal coil of approximately 1,000 turns on cores of compressed silicon steel filings. The resultant transverse pulsatinglr direct current is several volts for only one milliampere flowing through the field coil and longitudinally through the conductive films in parallel. I i

have found that where four amperes alternating current at (i0 cycle frequencyV is passed through a l2 turn coil and then through the conductive films connected in parallel with themselves longitudinally, the resulting pulsating direct current component across each conductive film is approximately 50 microvolts. When the conductive films in the number above referred to are connected in series transversely 200 micro-volts may be obtained. The values obtainable may readily be used in the operation of electron tubes. The arrangement of the apparatus is such that connections may be readily made with electron tube circuits directly in the input circuit of an electron tube as represented at Fig. 9 without the interposition of transformer systems.

When an iron core is used with the device of my invention with the proper permeability curve an asymmetric characteristic curve may be obtained with the device similar to that obtained with a triode tube. This ability of. the device. of my invention facilitates the generation of self oscillations in the device. The device when properly connected will, therefore, operate as an amplifier or as an oscillator in addition to its properties as a rectifier.

While I have described my invention in certain preferred embodiments, I desire that it be understood that various modifications may be made Without departing from the spirit of the appended claims.

What I claim as new and desire to secure by Letters Patentof the United State-3 is as follows:

l. An electrical apparatus comprising a plurality of rectangular metallic films having major and minor axes, an electrical circuit for creating a magnetic field about said l metallic films by a current which passes along the longitudinal axes of said metallic films in parallel for deriving a rectified current in a circuit including the transverse axes of said metallic films in series.

2. An electrical apparatus comprising a plurality of metallic films having their longitudinal axes exceediner their transverse axes in length, means insulating one of said metallic films from another of said metallic films, means bonding the ends of the longitudinal axes of said films in parallel, a circuit including a series path through the longitudinal axes of said metallic films for creating a magnetic field which encloses said films and an output circuit including the transverse axes of said films in series.

3. An electrical apparatus comprising a plurality of alternately positioned conductive and dielectric sheets each of said conductive sheets having longitudinal and transverse axes with the longitudinal axes exceeding the length of the transverse axes thereof, ctnnections between adjacent ends of said conductive sheets at the longitudinal axes thereof including a magnetic winding enclosings-aid shcetsfor subjecting all of said sheets to the effects of magnetic lines of force normal to the surfaces thereof, and a series connection between the transverse axis of adjacent conductive sheets.

4. An electrical apparatus comprising a stack of alternately positioned conductive films and dielectric sheets, each of said c0nductive films being connected together at adjacent ends along one axis thereof and connected in series between points along another axis thereo f, a magnetic field enclosing said films for subjecting all of said films to the effects of magnetic lines of force normalto the surface thereof.

-5. An electrical apparatus com rising a plurality of alternately positione conductive films and dielectric sheets, each of said conductive films being rectangular in shape and having their longitudinal axes connected together at adjacent ends, a series connection between opposite edges of adjacent conductive films along the transverse axes thereof and a magnetic Winding enclosing said films and dielectric sheets.

6. An electrical apparatus comprising a plurality of alternately positioned superimposed conductive and dielectric films each of said conductive films having a pair of normally disposed axes, connections between adjacent edges of said conductive films along one axis thereof and connections between opposite edges of adjacent conductive films along another axis thereof, and a winding disposed around said superimposed conductive and dielectric sheets.

7. An electrical apparatus comprising a plurality of alternately positioned superimposed conductive and dielectric films, each of said films being connected'in parallel along the longitudinal axes thereof and connected in series at the edges of said conductive films along the transverse axes thereof, and means for establishing a concentrated magnetic field normal to the plane of said conductive films.

8. Means for rectifying alternating current comprising a plurality of fiat alternately positioned conductive films and dielectric sheets aligned in superimposed relation, a circuit for connecting said conductive films in parallel at the edges thereof and ra sepa rate circuit for connecting said conductive films in series at the edges thereof at points removed from said aforementioned circuit, and means for enclosing said conductive films by ,a magnetic field extending substantially normal to the conductive films.

9. A system for modifying the character of electrical current comprising a plurality of conductive films'insulated one from another, each having longitudinally and transversely extending axes, separate electrical circuits connected across said transversely and longitudinally extending axes, and means for establishing a magnetic field normal to the planes of said films.

10. A system for amplifying fiuctuations of electrical voltage and power comprising l a plurality of conductive film's insulated one from another in superimposed relation, each having longitudinally and transversely extending axes, a winding enclosing said films for establishing a magnetic field surrounding the films, a circuit connectedacross said longitudinally extending axes, a separate circuit connected across said transversely extending axes, and means for subjectingsaid conductive films to theeffects of said transverse magnetic field in synchronism with said fluctuations whereby the fluctuations of the voltage and power in said last mentioned circuit are increased with respect to those in said first mentioned circuit.

11. In a system for modifying electrica currents the combination of a plurality of conductive films possessing the properties of Hall effect and havin 4longitudinal and transverse axes, means for insulating said films one from another, a winding producing an alternating transverse magnetic field penetrating said films, a multiplicity of separate circuits, one of said circuits being connected to said winding, another of said circuits being connected to said longitudinalaxes of said films and another ofsa-id circults belng connected with the transverse axes of said films, said circuits being connected for synchronous operation under control of the supplied current whereby energy supplied to one of said circuits effects another of said circuits for producing ener to the character of the impressed energy.

Uy modified with respect 12. In a system for modifying electrical currents the combination of a plurality of conductive films possessing the properties of Hall effect and having longitudinal and transverse axes, means for insulating said films one from another, a winding producing an alternating transverse magnetic field penetrating said films, a plurality of independent circuits one of said circuits being connected to said winding, another of said circuits being connected to said longitudinal axes of said films and still another of said circuits being connected with the transverse axes of said films, a source of energy connected in one of said circuits and means for supplying energy to another of said circuits in synchronism with the establishment of said alternating magnetic field for cont'rolling the Hall effect in said films and regulating the operation of said source of energy with respect to said circuits.

13. In a system for generating electrical oscillations the combination of a plurality of conductive films each possessing Hall effect and insulated one from the other, each having longitudinally and transversely extending axes, awinding producing a magnetic field for penetrating said films transversely 

